level playing field

We need a level playing field for soccer, so one team does not have to run uphill.

Meaning 2 ►▼

to be fair, to be equal

Sentence 2

They had more troops. We bombed them, so we had a level playing field before we sent in our troops.

Derivation

The idiom above, used in the Gulf War of 1990 refers to equalizing the numbers of ground troops rather than a level area for men to fight. In this case, the idiom is so far removed from its literal meaning of a flat or level field it becomes rather confusing.